ecological interface design

An approach to interface design that uses Rasmussen’s abstraction hierarchy and skills-rules-knowledge framework to specify interfaces that support adaptive human operator behavior in the face of events or situations that systems designers did not anticipate.

direct perception

The theory of James J. Gibson that claims that the visual environment is perceived “directly,” as opposed to being indirectly inferred from sense data.

design rationale

Arguments for why (or why not) a feature or set of features should be incorporated into a design.

design

Encompasses activities and actions directed at producing new artifacts. Design work is collective and multidisciplinary. It often includes professional designers, technologists, and future users of the artifacts.

descriptive model

A model that describes how a system or person behaves and that provides a framework or context for thinking about or describing a problem or situation. Usually based on data gained through empirical observation, it is often little more than a verbal or graphic articulation of categories or identifiable features in an interface.

DCog

The form of distributed cognition developed by Hutchins in the early 1990s. It is distinguished from other uses of the term distributed cognition by its explicitly computational perspective on goal-based activity systems.

CSCW

See computer-supported cooperative work.

critical path

The path through subtasks (operators) in a PERT chart that determines the length of the total task. Used in CPM-GOMS.

CPM-GOMS

A version of GOMS developed by John in the 1980s that explicitly joined GOMS to the model human processor. It included perceptual and motor operators as well as cognitive operators. Perceptual, cognitive, and motor operators could run in parallel, subject to resource and information dependencies. More information can be found in Gray, John, & Atwood, 1993; John 1988, 1990; John & Gray, 1992, 1994, 1995.

cost structure of information

An analysis of the resource and opportunity costs involved in accessing and handling information from a physical or virtual information system.